In a total knee replacement, the whole of the ends of the femur and tibia are usually removed, and replaced with metal and plastic. The articulating side of the patella may also be replaced.
Why are arthroplasties performed?
Pain from arthritis is the main reason for considering an arthroplasty.
By removing the damaged ends of the bone and replacing them with artificial materials the arthritic pain can be greatly reduced together with most deformity from the arthritic process.
The word 'arthro-plasty' means joint re-shaping, so the term includes all extents of knee replacement -
- unicompartmental (or partial) knee replacement
- total knee replacement
- interpositional arthroplasty (eg Unispacer) - this is not truly an arthroplasty but a replacement for a missing meniscus, to avoid damage to the joint itself.
Arthroplasty and the concept of 'compartments'
From the point of view of joint replacement, the knee is considered to have three compartments, and implants may replace any or all of them.
These include the two tibio-femoral compartments and the patello-femoral compartment.
A total knee replacement replaces the whole articulation of femur and tibia - both sides - and very often the patella also. A partial knee replacement is indicated when the joint destruction affects only part of the joint. So, for example, the replacement may be of just one of the condyles of the femur and the part of the tibia it articulates with.
This is an example of a partial arthroplasty, where only one side of the knee joint has been replaced.
Quick linksHow long does it take to recover from a knee replacement?
Every patient will be different, and age and fitness will be factors.
Muscle weakness and contraction may delay recovery. Usually patients are encouraged to bear weight very early, but full recovery may take many months.
When it comes to age, it is not so much actual age but biological age that affects decision-making. The key issue is that the artificial materials are subject to wear and tear, and most joint replacements only last for a decade or so and have to be replaced. So the surgeon avoids doing this procedure in the younger patient to avoid revision surgery.
Peer-reviewed papersQuote from peer-reviewed paper:
"...surgeon- and patient-reported outcomes have been shown to be disparate occasionally....In general, patients tend to be less satisfied with treatment outcomes than does the surgeon....attributed....mainly to the preoperative level of patient expectation and development of complications."
Citation: Choi YJ, Ra HJ. Patient Satisfaction after Total Knee Arthroplasty. Knee Surg Relat Res. 2016 Mar;28(1):1-15. doi: 10.5792/ksrr.2016.28.1.1. Epub 2016 Feb 29. PMID: 26955608; PMCID: PMC4779800.
Are there alternatives to knee replacement?
Realignment osteotomy is very valuable in the younger patient to change the forces going through an arthritic joint.
This will relieve the pain and may give the patient many years before an arthroplasty becomes necessary.
Quick linksForum discussions
- KNEE ARTHRITIS - Total Knee Replacement
Board packed with discussions about total knee replacement.
- KNEE ARTHRITIS - Unicompartmental knee replacement
Board focusing on unicompartmental knee replacement.